<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="vue.js"></script>
</head>
<body>
<div id="app">
    <a v-if="isLogin">{{user}}</a>
    <a v-else>登录</a>
</div>

<script>
    var app = new Vue({
        el: '#app',
        data: {
            isLogin: true,
            user: "武沛齐"
        }
    })
</script>
</body>
</html>